We applied AMS ¹⁴C dates, Mg/Ca estimated sea surface temperature (SST), planktonic foraminiferal abundance, coarse component and X-ray diffraction mineral composition analyses for an International Ocean Discovery Program (IODP) sediment Hole U1467C in the Maldives inner sea, to reveal factors that affected the depositional process in the Maldives inner sea over the past 30 kyr. We found that the linear sedimentation rate (LSR) in Holocene (6.8 cm/kyr) was obviously higher than that in glacial period (3.45 cm/kyr); the average SST during the Holocene was 2–3°C higher than that in glacial stage. High abundance of planktonic foraminifera occurred during the glacial period, which was consistent with the variation of pelagic biogenic component. Reef-sourced material showed apparent high percentage during the Holocene (43.5%), in contrast to the low values during the glacial stage (20.7%). Terrigenous matter, only accounting for a small percentage in carbonate platform, was relatively high during the glacial period than that in the Holocene. We therefore conclude that reef-sourced material, dominated in the glacial-interglacial sediment sources, was mainly affected by sea level and climate changes. During glacial stage, sea level low-stand and weakened weathering in Maldives limited the input of the eroded material into the inner sea, resulting in low LSR; while the Holocene high sea level accompanied with rapid growth of the reef atoll and enhanced weathering, brought more reef-sourced material to the inner sea, leading to increased LSR and lowered abundance of planktonic foraminifera. The sea level and climate-controlled reef-sourced material changes are the key to understand the sedimentary process of the Maldives inner sea. Our study will shed some light on the evolution of glacial-interglacial sedimentary process of carbonate platform.

我们应用了 AMS ¹⁴马尔代夫内海国际海洋发现计划 (IODP) 沉积物 Hole U1467C 的 C 日期、Mg/Ca 估计海面温度 (SST)、浮游有孔虫丰度、粗成分和 X 射线衍射矿物成分分析，以揭示影响过去 30 kyr 影响了马尔代夫内海的沉积过程。我们发现全新世的线性沉降速率（LSR）（6.8 cm/kyr）明显高于冰期（3.45 cm/kyr）；全新世的平均海温比冰川期高 2~3°C。冰川期浮游有孔虫高丰度，这与远洋生物成分的变化一致。在全新世 (43.5%) 期间，来自珊瑚礁的材料显示出明显的高百分比，与冰川期的低值 (20.7%) 形成对比。陆源物质在碳酸盐台地中仅占很小的比例，冰期比全新世高。因此，我们得出结论，在冰期-间冰期沉积物来源中占主导地位的礁源物质主要受海平面和气候变化的影响。冰川期，马尔代夫海平面低位和风化减弱，限制了侵蚀物质进入内海，导致LSR偏低；而全新世的高海平面伴随着珊瑚礁环礁的快速增长和风化作用的增强，将更多的珊瑚礁来源物质带入内海，导致LSR增加，浮游有孔虫丰度降低。海平面和气候控制的礁源物质变化是了解马尔代夫内海沉积过程的关键。我们的研究将为碳酸盐台地冰期-间冰期沉积过程的演化提供一些启示。